From b1a8d6976ff41a1cde84647b7dbade9316fbcecf Mon Sep 17 00:00:00 2001
From: ringabout <43030857+ringabout@users.noreply.github.com>
Date: Mon, 11 Sep 2023 16:54:41 +0800
Subject: [PATCH] fixes the `discVal` register is used after free in vmgen
 (#22688)

follow up https://github.com/nim-lang/Nim/pull/11955
---
 compiler/vmgen.nim | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/vmgen.nim b/compiler/vmgen.nim
index 05c0d2a677..2e54812a05 100644
--- a/compiler/vmgen.nim
+++ b/compiler/vmgen.nim
@@ -1822,7 +1822,6 @@ proc genCheckedObjAccessAux(c: PCtx; n: PNode; dest: var TDest; flags: TGenFlags
   let setLit = c.genx(checkExpr[1])
   var rs = c.getTemp(getSysType(c.graph, n.info, tyBool))
   c.gABC(n, opcContainsSet, rs, setLit, discVal)
-  c.freeTemp(discVal)
   c.freeTemp(setLit)
   # If the check fails let the user know
   let lab1 = c.xjmp(n, if negCheck: opcFJmp else: opcTJmp, rs)
@@ -1835,6 +1834,7 @@ proc genCheckedObjAccessAux(c: PCtx; n: PNode; dest: var TDest; flags: TGenFlags
   strLit.typ = strType
   c.genLit(strLit, msgReg)
   c.gABC(n, opcInvalidField, msgReg, discVal)
+  c.freeTemp(discVal)
   c.freeTemp(msgReg)
   c.patch(lab1)